1. Field of the Invention
The present invention relates to a treatment device for a medical treatment.
2. Description of the Related Art
In general, a treatment device for a medical treatment is known which treats a biotissue by use of heat energy. For example, in Jpn. Pat. Appln. KOKAI Publication No. 2001-190561, the following treatment device for the medical treatment is disclosed. This treatment device for the medical treatment has an openable/closable holding portion to hold a biotissue that is a treatment object. In this holding portion, a resistance element is disposed which functions as a heater to heat the holding portion. In such a treatment device for the medical treatment, the biotissue is held by the holding portion, and the biotissue of the held portion is heated, whereby the biotissue can be anastomosed. As to control of an amount of power to be supplied to the resistance element, in Jpn. Pat. Appln. KOKAI Publication No. 2001-190561, there are disclosed a control method of supplying the power of the amount of a predetermined constant value, and a method of controlling a temperature of the resistance element to a predetermined temperature by feedback control while performing temperature measurement on the basis of a change of a resistance value of the resistance element.
In use of such a treatment device for a medical treatment as described above, it is general that an area of a biotissue to be held by a holding portion during anastomosis is not constant and varies in every treatment. Consequently, in a control method in which an amount of power to be supplied to a resistance element that functions as a heater is set to a predetermined constant value, an anastomosis temperature varies in every treatment. As a result, there is the possibility that a joining strength becomes unstable. On the other hand, in a method in which the temperature of the resistance element is controlled to a predetermined temperature by feedback control while performing temperature measurement on the basis of a change of a resistance value of the resistance element, it is necessary to accurately acquire characteristics of a relation between the resistance value and the temperature of the resistance element in advance. For this purpose, it is necessary to manage uniformity of the resistance element with high precision during manufacturing, or to accurately measure the resistance-temperature characteristics of the resistance element individually. As a result, costs of the device increase disadvantageously. Furthermore, in the feedback control, the temperature control to be executed tends to be complicated.